1. Field of the Invention
The present invention relates to a process and apparatus for the detection of drugs and other biochemicals present in a human or other mammalian system and the reporting of the detection telemetrically to a receiver. The present invention is particularly suited for monitoring parolees and others for drug use, monitoring medical conditions of patients, and remote monitoring of biochemical parameters of subjects in space.
2. Background Art
Agencies of the criminal justice system utilize a variety of techniques for monitoring convicted persons either in institutions or in various less secure settings within the community. One successful method for monitoring convicts in a non-institutionalized setting employs a telemetry bracelet for locating persons at home or at work locations. In these systems, a device attached to the paroled convict signals a receiver attached to a telephone system to report the convict's whereabouts relative to the receiver. Parole conditions may also include prohibitions on the use of controlled substances, especially in cases of convictions involving drug use. Additionally, convicts who are incarcerated are also supposed to be prohibited from using controlled substances during incarceration. Due to manpower and budgetary constraints, only a small fraction of the existing parolees can be tested for drug use at any one time. Therefore, for these types of situations, it would be desirable for telemetry devices, similar to those presently being used for the parolees, such as telemetry bracelets, to actively monitor for the presence of controlled bioactive substances in a non-invasive and continuous way.
In a medical setting, hospitals and home care medical care operations require that various biochemical parameters be carefully monitored. For example, diabetics must control their blood sugar levels and blood insulin levels carefully. Patients with infections must maintain a minimum antibiotic level in their system. Patients with various chronic ailments are required to take regular doses of medication, such as epileptic patients on anti-epileptic drugs. The continuous and non-invasive monitoring of such patients is also desirable. The medical community may also find it desirable to monitor the levels of prescribed medications and detect overdoses of such medications in order to come to the aid of such patients as soon as the problem is detected.
Such sensor/telemetry technology has applications to NASA activities as well where biological substance detection could be employed in process control for life support systems and in the remote manipulation and analysis of space borne biological and medical experiments.
Liotta, U.S. Pat. No. 4,837,145 discloses a device for determining the presence of an antigen which comprises a trapping zone, which contains material capable of capturing free flowing enzyme linked antibodies, but not antibodies bound to a transport particle which flows freely through the trapping zone into the substrate zone, and a substrate zone which contains material capable of reacting with enzyme-linked antibodies to produce a reaction which indicates the presence of antibodies. A method of determining the presence of an antigen is also disclosed wherein a sample is mixed with two classes of antibodies which are specific for the antigen being tested for, but which react with different antigen domains, wherein the mixture consists of class one antibodies bound to a transport particle which flows freely through the trapping zone and class two enzyme-linked antibodies which are incapable, unless bound to the transport particles, of flowing freely through the trapping zone. In the presence of the antigen being tested for, both classes of antibodies bind to the antigen and flow through the trapping zone into the substrate zone, wherein a reaction takes place to indicate the presence of the antigen.
Liotta, U.S. Pat. No. 4,446,232 discloses a device for determining the presence of antigens which comprises a first zone containing antigens and enzyme-linked antibodies which are capable of immunologically reacting with said antigens, said antibodies being positioned in said first zone such that they will be removed from said first zone when reacted with antigens passing through said first zone but not removed from said first zone in the absence of such antigens, and a second zone containing material capable of reacting with said enzyme-linked antibodies to produce a color forming reaction which indicates the presence of said antibodies. Hiratsuka et al., U.S. Pat. No. 4,337,065 also discloses a multilayer device for determining antigens similar to U.S. Pat. No. 4,446,232 except for the detection being by development of a silver halide film.
In 1991, Dr. David Kidwell reported the development of a simple to use device for field testing urine and saliva for the presence of drugs of abuse, specifically, cocaine. The device is called a microassay on a card, or MAC. It consists of a small flat plastic card (2 inches.times.2 inches.times.0.2 inches) in which all of the reagents required for the cocaine assay are provided. To run the test, a sample of saliva or urine, 50 .mu.l, is placed in a well; the urine or saliva is drawn through a semipermeable membrane into the MAC via capillary action. If the drug is present, a calorimetric reaction occurs and becomes visible within 5 minutes on the card. The MAC test is more fully described in U.S. Pat. Nos. 5,200,321 and 5,369,007, incorporated herein by reference. As described in U.S. Pat. No. 5,200,321, the microassay card includes an upper layer containing wells for receiving a liquid sample, a second layer of the card, beneath the first layer, which includes a supporting surface bound to a reactive species, and a third layer which includes an absorbent support impregnated with an indicator. Typically, the indicator is a substrate for an enzyme, such as a reduced dye precursor and a source of hydrogen peroxide necessary for the action of the enzyme upon the substrate to cause a spectral change in the absorbent layer. The microassay card is particularly useful for drug testing.
The MAC operates by virtue of an antibody-antigen interaction. Disposed within the MAC is an absorbent paper layer to which a drug sample (antigen) is covalently bound. Enzyme labeled anti-drug antibodies are immobilized on this layer by an antigen-antibody interaction. If the drug to be detected is present in the saliva or will displace the bound anti-drug antibody, which then can travel through the system and reach a layer of substrate. The enzyme attached to the antibody causes the substrate to change color, giving a visual signal for presence of the drug.
It would thus be desirable to provide a system which integrates the microassay system with a sensor/telemetry system with a wide range of potential applications. The applications are limited then only by the availability and stability of the biological reporter molecules such as antibodies, enzymes, and the like.